Semi-trailers are typically detachable from either direct drive tractor units or from other trailers, for example, another trailer in a B-double, B-triple, or semi-trailers in a road train as used in countries such as, but not limited to, Australia.
Preventing thefts of semi-trainers is of economic importance on several grounds. For example, the theft of dropped semi-trailers results in losses to the insurance industry. In addition, businesses are affected by a non-delivery of goods. The distribution of gasoline or diesel is disrupted when semi-trailers carrying gasoline or diesel are stolen. Semi-trailers loaded with expensive goods such as high-end kitchen appliances, if stolen, cause significant business losses. Thus, there is a need for devices to reduce theft of detachable semi-trailers.